Tris(pentane-2,4-dionato-O,O')vanadium

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

Information not available.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: The 24 hour TT (toxicity threshold) values of 156 hazardous substances for algae species Scenedesmus quadricauda was determined by means of a standardized procedure (Cell Multiplication Inhibition Test). The present study of the potential toxic action of water pollutants on water micro-organisms has been performed with special reference to the toxicity for model organisms of biological self-purification by determining the toxicity thresholds (TT) for Pseudomonas putida (bacteria);. Scendesmus quadriceuda (green algae) and Emosiphon sulcatum (protozoa).This work has contributed to the creation of a scientific basis for corresponding legislation.
- Short description of test conditions: As a method of the toxicologica! study, the cell multiplication inhibition test was applied to the desribed three model organisms. Pure cultures of single-ceil mode! organisms are used in the tests. Culture media and conditions for the preparation of stock cultures, preliminary cultures, and test cultures of the model organisms are standardized, Inoculum, cell multiplication, and its inhibition are determined quantitatively.
- Parameters analysed / observed: Toxicity Threshold (pollutant concentrations at which the onset of inhibitory action was observed)

GLP compliance:

no

Specific details on test material used for the study:

Results are for Acetylacetone (IUPAC name: 2,4 -pentandione; CAS No. 123 -54 -6) a degradation product of Vanadium-(III)-acetylacetonate).

Analytical monitoring:

no

Details on sampling:

- Concentrations: Artifical freshwater (containing nutrient solutions) was used as test medium. Dilution series of the chemical compounds were prepared by dilution of a stock solution with sterile double-distilled tap water. These dilutions each contain 1 part (v/v) of pollutant solution in 2.0E+0 to 2.0E+14 parts (v/v) mixture. When preparing the two parallel dilution series in 300-mL Erlenmeyer flasks following procedure was applied: The first flask of each dilution series contains 80 mL of pollutant solution at the start. Starting from this flask, prepare subsequent dilutions using a constant dilution ratio of 40 mL preliminary pollutant dilution + 40 mL double-distilled water. So each flask will first contain 40 mL of liquid. Then, complete each flask from the dilution series to be inoculated to the rated value of 50 mL by adding 5 mL each of stock solution I and 5 mL each of the algal suspension of the preliminary culture having a known adjusted extinction value. Detailed information about final applied dosages of test compounds not available.
- Sampling method: Information not available.
- Sample storage conditions before analysis: Information not available.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances):
As test medium "artificial freshwater" was prepared by adding of specific nutrient solutions. Dilution series of the chemical compounds were prepared by dilution of a stock solution with sterile double-distilled tap water. These dilutions each contain 1 part (v/v) of pollutant solution in 2.0E+0 to 2.0E+14 parts (v/v) mixture.

Test organisms (species):

Scenedesmus quadricauda

Details on test organisms:

TEST ORGANISM
- Common name: Green algae Scenedesmus quadricauda
- Strain: Not reported.
- Source (laboratory, culture collection): Laboratory culture (see cultivation description below).
- Age of inoculum (at test initiation): Preliminary cultures were were kept for 10 days prior to test period.
- Method of cultivation: Store stock cultures of the test strain Scenedesmus quadricauda in 20 mL nutrient solution No. 1 in 100-mL Erlenmeyer flasks stoppered with metal caps, on a white surface protected against daylight and exposed to constant lighting by luminescent worm white tubes at 60 cm distance from each other, at 27°C and a relative humidity of 50%. For maintenance of the test strain, prepare fresh stock cultures continuously at 10 days' intervals. For this purpose sterilize the required number of Erlenmeyer flasks containing 20 mL of nutrient solution No. 1 and stoppered with metal caps in a steam sterilizer for 30 min each on two consecutive days. When cool, inoculate the contents of each flask with 2 mL cell suspension from a 10-day stock culture.
Prepare preliminary cultures in the same way; keep them under conditions identical to those for stock cultures for 10 days. Cell material from the preliminary cultures is used to inoculate the test cultures. To prepare for this, separate the algae from the culture solution by membrane filtration in a sterilized filtration device. Wash the separated cell material on the filter with 100 mL of sterilized double-distilled water and take up in 100 mL of sterilized double-distilled water. Determine by photoelectric measurement the extinction of the monochromatic radiation at 578 nm for a 10-mm layer of the algal suspension. On the basis of the value measured, adjust the final turbidity value of the algal suspension by dilution with sterile double-distilled water so that in a measuring sample prepared by dilution 1 + 9 with double-distilled water, the extinction value will correspond to the extinction value of the Formazin standard suspension TE/F/578 nm = 20. Turbidity is determined according to German method DEV C.2 (Bestimmung der Trübung"; i.e. Determination of Turbidity).
Before preparing the test cultures neutralize the solution having a known pollutant content in sterile double-distil led water to be tested using the minimum volume acid or alkaline solution.

ACCLIMATION
- Acclimation period: Preliminary cultures were were kept for 10 days prior to test period.
- Culturing media and conditions (same as test or not): Stock- and preliminary-cultures were kept with a specific nutrient solution ("Nutrient solution No. I"), whereas test cultures were cultivated with a different nutrient mixture ("Stock solution I, for test cultures"). Detailed composition and dosage of the mineral solutions are available in the publication. Stock cultures of the test strain Scenedesmus quadriccuda were stored in 20 mL nutrient solution No. I in 100-mL Erlenmeyer flasks stoppered with metal caps, on a white surface protected against daylight and exposed to constant lighting by luminescent worm white tubes at 60 cm distance from each other, at 27°C and a relative humidity of 50%.
- Any deformed or abnormal cells observed: Not observed.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

24 h

Post exposure observation period:

No additional period implemented in test design to perform post-exposure observations.

Hardness:

Information not available.

Test temperature:

27°C

pH:

pH values of nutrient solutions was adjusted 7.0 (with Na2CO3). After final dilution no further pH adjustment was performed.

Dissolved oxygen:

Information not available.

Salinity:

Parameter not relevant since freshwater was used as test medium.

Conductivity:

Information not available.

Nominal and measured concentrations:

Only nominal test concentrations available.

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks of 100 mL capacity, filled with 50 mL test solution and algal suspension)
- Type (delete if not applicable): Stock solution flasks were stoppered with metal caps. Further details not available.
- Material, size, headspace, fill volume: Glass Erlenmeyer flasks, capacity 100 mL, filled with 50 mL.
- Aeration: Information not available.
- Type of flow-through (e.g. peristaltic or proportional diluter): Not relevant, test was performed under static conditions.
- Renewal rate of test solution (frequency/flow rate): Not applicable, static test conditions..
- No. of organisms per vessel: Addition of 5 mL of algal suspension per vessel.
- No. of vessels per concentration (replicates): 2 vessels per concentration.
- No. of vessels per control (replicates): 1 vessel.
- No. of vessels per vehicle control (replicates): No vehicle used.
- Biomass loading rate: Information not available.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: De-ionizid tap water was used to prepare artificial freshwater.
- Total organic carbon: Information not available.
- Particulate matter: Information not available.
- Metals: Information not available.
- Pesticides: Information not available.
- Chlorine: Double deionised tap water was used for dilution of the prepared mineral solutions. These nutrient solutions contained chloride (no detection results reported).
- Alkalinity: pH values of nutrient solutions was adjusted 7.0 (with Na2CO3. After final dilution no further pH adjustment was performed.
- Ca/Mg ratio: Information not available.
- Conductivity: Information not available.
- Salinity: Not relevant as tap water was used as test medium.
- Culture medium different from test medium: Yes, different nutrent solutions were applied. Detailed composition available in the publication.

Information not available.
- Intervals of water quality measurement: Information not available.

OTHER TEST CONDITIONS
- Adjustment of pH: No, pH value was not changed. Only pH value of nutrient solution prior to dilution was adjusted to 7.0.
- Photoperiod: Stock cultures of the test strain Scenedesmus quadriccuda were stored in 20 mL nutrient solution No. I in 100-mL Erlenmeyer flasks stoppered with metal caps, on a white surface protected against daylight and exposed to constant lighting by luminescent worm white tubes at 60 cm distance from each other, at 27°C and a relative humidity of 50%.
- Light intensity: Information not available.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): The 24 hour TT-values (toxicity threshold) values were determined by means of a standardized procedure (Cell Multiplication Inhibition Test) under static conditions. The Toxicity Threshold is defined as the pollutant concentration at which the onset of inhibitory action is observed.

VEHICLE CONTROL PERFORMED: Not applicable, vehicle was not used in this test.

RANGE-FINDING STUDY: No range-finding study performed.

Reference substance (positive control):

no

Remarks:

The study comprise investigation of 156 chemical compounds for their acute toxicity to algae. Hence the plausibility of results for the test compound could be compared with the observed toxicity of the other chemicals.

Duration:

24 h

Dose descriptor:

other: Toxicity threshold (TT)

Effect conc.:

2.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: The Toxicity Threshold is defined as the pollutant concentration at which the onset of inhibitory action is observed.

Remarks on result:

other: Result for Acetylacetone (IUPAC name: 2,4 -pentandione; CAS No. 123-54-6)

Details on results:

- Exponential growth in the control (for algal test): Information not available.
- Observation of abnormalities (for algal test): None
- Unusual cell shape: Not observed.
- Colour differences: Not observed.
- Flocculation: Not observed.
- Adherence to test vessels: Not observed.
- Aggregation of algal cells: Not observed.
- Any stimulation of growth found in any treatment: Not observed.
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No such effects observed.
- Effect concentrations exceeding solubility of substance in test medium: Not relevant in case of the test compound.

Results with reference substance (positive control):

No reference substance was used. However, the study comprise investigation of 156 chemical compounds for their acute toxicity to algae. Hence the plausibility of results for the test compound could be compared with the observed toxicity of the other chemicals.

Reported statistics and error estimates:

For evaluation of toxicological findings at the end of the test period, the mean value (A) of the extinction is calculated for all test cultures that are free from toxic influence and stimulation of growth, except for those having extinction values outside a standard deviation of <3% and also, the mean value (B) of the extinction for those test cultures having the lowest toxic pollutant concentration within the dilution series. For mathematical evaluation by means of a suitable electronic calculator, (a) (highest non-toxic pollutant concentration) is plotted against (A) and (b) (lowest toxic pollutant concentration) against (B) as coordinates. After entering (A - 3%), the pollutant concentration at which inhibitory action begins (c) may be obtained from the regression line between (a;A) to (b;B) if a negative deviation of the mean extinction by a 3% difference against the mean extinction value for all test cultures having a non-toxic and non-stimulating pollutant concentration is used as an indicator of the beginning of inhibitory action.

It should become evident from the results of such study that the damaging action of water pollutants is selectively directed against one group of model organisms, depending upon the different chemical nature and group classification of the pollutants involved.

Validity criteria fulfilled:

not specified

Conclusions:

The 24 hour TT-values (toxicity threshold) values of 156 substances hazardous in water to algae species Scenedesmus quadricauda were determined by means of a standardized procedure (Cell Multiplication Inhibition Test) under static conditions. The Toxicity Threshold is defined as the pollutant concentration at which the onset of inhibitory action is observed. Result for Acetylacetone (IUPAC name: 2,4 -pentandione; CAS No. 123-54-6) .
Toxicity Threshold (TT) for Acetylacetone (IUPAC name: 2,4 -pentandione; CAS No. 123-54-6) was: TT = 2.7 mg/L (nominal concentration).

Executive summary:

The 24 hour TT-values (toxicity threshold) values of 156 hazardous substances for green algae species Scenedesmus quadricauda were determined by means of a standardized procedure (Cell Multiplication Inhibition Test). The test was performed under static conditions. The Toxicity Threshold is defined as the pollutant concentration at which the onset of inhibitory action is observed. One of the investigated chemicals was Acetylacetone (IUPAC name: 2,4 -pentandione; CAS No. 123-54 -6), a degradation product of Vanadium-(III)-acetylacetonate.

This work has contributed to the creation of a scientific basis for corresponding legislation. Pure cultures of single-cell model organisms were used in the test. Culture media and conditions for the preparation of stock cultures, preliminary cultures, and test cultures of the model organisms were standardized, Inoculum, cell multiplication, and its inhibition were determined quantitatively. The present study of the potential toxic action of water pollutants on water micro-organisms has been performed with special reference to the toxicity for model organisms of biological self-purification by determining the toxicity thresholds (TT) for Pseudomonas putida (bacteria), Scenedesmus quadricauda (green algae) and Entosiphon sulcatum (protozoa). As test medium "artificial freshwater" was prepared by adding of specific nutrient solutions. Dilution series of the chemical compounds were prepared by dilution of a stock solution with sterile double-distilled tap water. These dilutions each contain 1 part (v/v) of pollutant solution in 2.0E+0 to 2.0E+14 parts (v/v) mixture.

The concentration of the algal suspension was measured turbidimetrically (while diffused light is screened off) and expressed by the extinction of the primary light of the monochromatic radiation at 578 nm for a layer of 10 mm thickness. The concentration at which the inhibitory action of a pollutant begins is present in that dilution from a series of dilutions of a pollutant having, at the end of the test period, a mean extinction value that is >=3% below the mean value of the extinction value for non-toxic dilutions of the test cultures.

Results: From the number of 156 inorganic and organic pollutants tested, 23 exhibited a pronounced selective toxic action on bacteria or the species Pseudomonas putida, 47 on algae of the species Scenedesmus quadricauda, and 43 on flagellate protozoa of the species Entosiphon sulcatum. Toxicity Threshold (TT) for Acetylacetone (IUPAC name: 2,4 -pentandione; CAS No. 123 -54 -6) was: TT for Scenedesmus quadricauda = 2.7 mg/L (nominal concentration).

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Remarks:

Three phytoplankton species were investigated (Dunaliella marina, Prorocentrum micans and Asterionella japonica)

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

please refer to Read-across statement attached in section 13

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

9 d

Dose descriptor:

EC50

Remarks:

converted to VAA

Effect conc.:

3.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Result for Dunaliella marina

Remarks:

for details on the calculation, please refer to 'Overall remarks'

Key result

Duration:

9 d

Dose descriptor:

EC50

Remarks:

converted to VAA

Effect conc.:

13.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Result for Asterionella japonica

Remarks:

for details on the calculation, please refer to 'Overall remarks'

Key result

Duration:

9 d

Dose descriptor:

EC50

Remarks:

converted to VAA

Effect conc.:

20.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Result for Prorocentrum micans

Remarks:

for details on the calculation, please refer to 'Overall remarks'

Duration:

15 d

Dose descriptor:

EC100

Remarks:

converted to VAA

Effect conc.:

ca. 6.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Result for Dunaliella marina

Remarks:

for details on the calculation, please refer to 'Overall remarks'

Duration:

15 d

Dose descriptor:

EC100

Remarks:

converted to VAA

Effect conc.:

ca. 683.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

not specified

Remarks on result:

other: Result for Asterionella japonica

Remarks:

for details on the calculation, please refer to 'Overall remarks'

Details on results:

- Exponential growth in the control (for algal test): yes/no
- Observation of abnormalities (for algal test):
- Unusual cell shape:
- Colour differences:
- Flocculation:
- Adherence to test vessels:
- Aggregation of algal cells:
- Other:
- Any stimulation of growth found in any treatment:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:
- Effect concentrations exceeding solubility of substance in test medium:

Results with reference substance (positive control):

No reference substance (positive control) investigated.

Considering the results from LC50 (9 days) experiments, the organisms, can be classified in the following decreasing order of sensitivity: Dunaliella marina (0,5 mg/L), Asterionella japonica (2 mg/L), Prorocentrum micans (3 mg/L), Nereis diversicolor (10 mg/L), Carcinus maenas (35 mg/L), Mytilus galloprovincialis (65 mg/L).

Validity criteria fulfilled:

not specified

Conclusions:

The acute toxicity of vanadium as sodium metavanadate to three phytoplankton species (Dunaliella marina, Prorocentrum micans and Asterionella japonica) was studied. Considering the results from LC50 (9 days) experiments, the organisms, can be classified in the following decreasing order of sensitivity: Dunaliella marina (EC50 = 0.5 mg/L), Asterionella japonica (EC50 = 2 mg/L), Prorocentrum micans (EC50 = 3 mg/L). Converted to the target substance vanadium acetylacetonate these values correspond to EC50 values of 3.4 , 13.7 and 20.5 mg/L.

Executive summary:

The acute toxicity of vanadium as sodium metavanadate to three phytoplankton species was studied: Dunaliella marina (Chlorophycae), Prorocentrum micans (Dinoflagellatae) and Asterionella japonica (Diatomacea). The marine water used for this study had a natural background concentration of 1.7 µg/L Vanadium. For the phytoplankton species 13 concentration levels between 0.1 and 100 mg/L vanadium were investigated.

Total exposure period was 15 days with daily evaluation of the aquatic toxicity. EC50 values were determined (specified by authors as LC50, i.e. Lethal concentration of vanadium for 50% of population) were determined for the three species. Temperature of marine water was 14°C, salinity detection revealed a value of 38 per mille. All phytoplankton species were laboratory cultures. The test medium was not changed during the exposure period, i.e. static conditions) were implemented.

Results: In general, the phytoplankton species were found to be more sensitive than the benthic organisms used in the experiments.

Considering the results from LC50 (9 days) experiments, the organisms, can be classified in the following decreasing order of sensitivity: Dunaliella marina (EC50 = 0.5 mg/L), Asterionella japonica (EC50 = 2 mg/L), Prorocentrum micans (EC50 = 3 mg/L). Converted to the target substance vanadium acetylacetonate these values correspond to EC50 values of 3.4, 13.7 and 20.5 mg/L.

Description of key information

The parent compound Vanadium-tris-acetylacetonate is rapidly hydrolysed to 2,4 -pentanedione (CAS no. 123 -54 -6) and Vanadyl acetylacetonate (CAS no. 3153 -26 -2) in the presence of water (> 80% hydrolysis after 1h at pH 1.2, 4, 7 and 9). Hence, the half life is e.g. max. 1/48 of the test duration when put into aqueous test systems (e.g. daphnia (48 h test duration) or algae (72 h test duration) acute toxicity tests). Accordingly, the substance as such does not need to be tested in those systems and reliable data gained with the hydrolysis products 2,4-Pentadione (Cas no. 123-54-6) and Vanadyl acetylacetonate (3153-26-2) or comparable inorganic Vanadium compounds are used to adress the endpoint, which is entirely appropriate to draw conclusions on the toxicity of Vanadium-tris-acetylacetonate to aquatic algae and cyanobacteria.

freshwater species

Scenedesmus quadricauda, 2,4 -pentanedione, freshwater, static, Toxicity Threshold (24 h) = 2.7 mg/L

marine species

Dunaliella marina, NaVO₃, saltwater, static, EC50 (9 d) = 0.5 mg V/L - VAA EC50 (9 d) = 3.4 mg VAA/L

Asterionella japonica, NaVO₃, saltwater, static, EC50 (9 d) = 2 mg V/L - VAA EC50 (9 d) = 13.7 mg VAA/L

Prorocentrum micans, NaVO₃, saltwater, static, EC50 (9 d) = 3 mg V/L - VAA EC50 (9 d) = 20.5 mg VAA/L

Key value for chemical safety assessment

EC50 for marine water algae:

3.4 mg/L